Hose clamps have been designed in a great variety of forms which fall into three general types. A first of these types is a continuous band which includes an upstanding portion or "ear" which can be deformed permanently after assembly to tension the band around a hose. Such clamps are sometimes referred to as Oetiker clamps after the name of the inventor.
A second type of clamp includes a mechanical actuator, such as a worm screw, acting directly on a band to bring the band into firm engagement with the hose. Lastly, the third type is a clamp of spring steel made to have a diameter slightly less than that of the outside diameter of the hose, so that when the clamp is deformed and positioned on the hose, there will be stored energy in the clamp to apply a compressive radial force to hold the clamp on the hose. The present invention provides a clamp of the third type.
Clamps of the present type are first enlarged at the point of manufacture and retained in this condition either by mechanical interference between ends of the clamp or by a separate keeper in the form of a clip which is added to hold the clamp in the enlarged prestressed condition.
Clamps which use clips suffer from the possibility that energy stored in the clamp will propel the clip and cause it to be lost. This problem is exacerbated when used in automobiles because the clip could become lodged anywhere in the engine compartment.
By contrast those clamps which rely on inter-engagement of the ends to hold the clamp open are not always easy to release because of the problems of accessibility and the need for special tools.
Accordingly, it is an object of the present invention to provide a clamping device which can be delivered in a prestressed condition and which can be released easily using standard tools to facilitate placement on a deformable tube to create radial compressive stress in the tube.